The Standard Model of particle physics demonstrates a remarkable accuracy for predicting the results of particle physics experiments, but it is unable to answer some fundamental questions, such as why there is more matter than anti-matter in the Universe and what dark matter is. Several new facilities have been proposed to challenge our current, incomplete knowledge. A realistic step to progress would be to complement the high-luminosity LHC with an electron energy recovery Linac (ERL) to synchronously operate proton-proton with electron-proton: the Large Hadron electron Collider. The LHeC might be the possibly cleanest high resolution microscope of the world, a device which would be dedicated to Higgs physics, searches for new phenomena and high precision electroweak and QCD physics. In this talk I shall illustrate the LHeC opportunity, highlighting its physics potential as well as the current developments on the design of the ERL and of the detector. An outlook on the electron-proton facility proposed for the future circular collider (FCC) at CERN will also be given.